1. Field of the Invention
The present invention relates generally to doors for modules of semiconductor processing equipment, and more particularly to tolerance resistant and vacuum compliant door hinges having open assist features.
2. Description of the Related Art
In the manufacture of semiconductor devices, process chambers are interfaced to permit transfer of wafers, for example, between the interfaced chambers. Such transfer is via transport modules that move the wafers, for example, through slots or ports that are provided in the adjacent walls of the interfaced chambers. For example, transport modules are generally used in conjunction with a variety of substrate processing modules, which may include semiconductor etching systems, material deposition systems, flat panel display etching systems, etc. Due to the growing demands for cleanliness and high processing precision, there has been a growing need to reduce the amount of human interaction during and between processing steps. This need has been partially met with the implementation of transport modules which operate as an intermediate handling apparatus (typically maintained at a reduced pressure, e.g., vacuum conditions). By way of example, a transport module may be physically located between one or more clean room storage facilities where substrates are stored, and multiple substrate processing modules where the substrates are actually processed, e.g., etched or have deposition performed thereon. In this manner, when a substrate is required for processing, a robot arm located within the transport module may be employed to retrieve a selected substrate from storage and place it into one of the multiple processing modules.
As is well known to those skilled in the art, the arrangement of transport modules to "transport" substrates among multiple storage facilities and processing modules is frequently referred to as a "cluster tool architecture" system. FIG. 1A depicts a typical semiconductor process cluster architecture 100 illustrating the various chambers that interface with a transport module 106. Transport module 106 is shown coupled to three processing modules 108a-108c which may be individually optimized to perform various fabrication processes. By way of example, processing modules 108a-108c may be implemented to perform transformer coupled plasma (TCP) substrate etching, layer depositions, and/or sputtering.
Connected to transport module 106 is a load lock 104 that may be implemented to introduce substrates into transport module 106. Load lock 104 may be coupled to a clean room 102 where substrates are stored. In addition to being a retrieving and serving mechanism, load lock 104 also serves as a pressure-varying interface between transport module 106 and clean room 102. Therefore, transport module 106 may be kept at a constant pressure (e.g., vacuum), while clean room 102 is kept at atmospheric pressure. The processing modules 108a-108c are generally positioned very close to the transport module 106, and each tends to block physical access to the transport module 106 by service personnel who need to access the transport module 106 via a cover 109 of the transport module 106. Thus, in many cases there is only a narrow passageway extending between adjacent processing modules 108a-108c to the transport module 106. As a result, there is a significant limitation on the physical force that an operator can exert on a hatch 111 of the cover 109, such as for opening the hatch 111. Since ergonomic specifications assume that the service personnel are able to exert thirty pounds of force to open the hatch, the narrowness of the passageway may make it very difficult to open the hatch without mechanical or other non-human assistance.
One type of cover 109 is shown in FIG. 1B provided with the hatch 111 mounted on a fixed hinge 114. The hatch 111 has a hatch sealing surface 116 designed to seal when it is parallel to a cover sealing surface 117. The hatch 111 rotates on a pin 118, but depending on various manufacturing tolerances, the final rotational movement of the hatch 111 may not position the hatch sealing surface 116 parallel to the cover sealing surface 117. Thus, an angle X may result, such that an O-ring 119 between the hatch 111 and cover sealing surface 117 will be unevenly squeezed. As the hatch 111 moves further toward the cover 109 as a vacuum is drawn in the vacuum chamber that is to be closed by the cover 109, the angle X may increase, and result in an improper seal.
In an attempt to avoid such problems with the non-parallel sealing surfaces 116 and 117, and to comply with the ergonomic specifications, some have held a sealing surface 116 parallel to a cover sealing surface 117 using an air or hydraulic cylinder 121 which may raise or lower the hatch 111 out of or into sealing relationship with the cover 109. As noted, the ergonomic specifications require that hatches weighing more than 30 pounds be provided with mechanical or other non-human assistance to open the hatch 111. Thus, if the cylinder 121 reduces to less than thirty pounds the force that a human must exert to open the hatch 111, the cylinder 121 meets these specifications. However, as shown in FIG. 1C, the cylinders 121 are generally mounted in positions near the hatch 111, and may block access to a port 122 and to the inside of the vacuum chamber once the hatch 111 has been opened. Also, these cylinders 121 tend to be costly, and are generally used where it is desired to lift the entire cover 109, rather than only the hatch 111. Further, safety precautions may require that both hands of the service personnel be away from the hatch 111 during operation of the cylinder 121. Because the hatch 111 may weigh thirty-five or fifty pounds, for example, once the hatch 111 has been opened, safety requirements provide that a latch must be used to prevent sudden closing of the hatch 111.
To avoid the limitations of such cylinders 121, some have pivotally mounted the entire cover 109 as shown, for example, in FIG. 1D, for motion from a closed (C) position to an open (O) position. However, in addition to having to move the greater weight of the cover 109 (e.g., 500 pounds) as compared to the lesser weight of the hatch 111, the larger size cover 109 tends to block access to electrical panels 123, for example.
In view of the forgoing, what is needed is a hatch for covers of modules of semiconductor processing equipment, where the hatch is mounted by hinges that are tolerance resistant, vacuum compliant, and have open-assist features.